I did consider this. My take on it was that we probably don't want to do validation in our importer, and then do validation again inside the downloader. It's not uncommon for libraries to fail ungracefully when given incorrect types in Python, so I think leaving validation to user-facing code (like the CLI and the importer) is reasonable. The doc-block about this item does mention that it should be an integer (and doesn't mention that a string of an integer will also work, even though it will).